A unique code that identifies the particular error condition that occurred. Your application can use error codes as identifiers in your customized error-handling algorithms. See the "Errors by Number" document.

Indicates whether the error message text is intended to be displayed to an end user or intended only to be parsed by the application. If true or not present (the default), the message text is intended for the end user. If false, the message text is intended for the application, and the application should translate the error into a more appropriate message. Only applicable to Item Specifics errors and warnings returned from listing requests.